Sterling silver alloy



United States Patent STERLING SILVER ALLOY Jacob S. Shelf, Flushing, N. Y.

No Drawing. Application July 9, 1951, Serial No. 235,911

3 Claims. (Cl. 75-173) This invention relates to an alloy and refers more particularly to an alloy capable of use as sterling silver.

One object of the present invention is the production of a sterling silver which is non-tarnishing and non-corrodible for all practical purposes.

A further object of the present invention is the provision of a pre-alloy which can be conveniently combined with silver to produce sterling silver which is completely non-tarnishing and non-corrodible.

A still further object of the present invention is the provision of non-tarnishing and non-corrodible sterling silver which can be conveniently adapted for the manufacture of silverware, hollowware, ornamental jewelry, dental amalgam and silver solder, and/ or any place where sterling silver in any form is used.

The above and other objects of the instant invention will become apparent in the course of the following specification.

This application for patent is a continuation of earlier application Serial Number 130,859, filed December 2, 1949, now abandoned.

The objects of this invention may be realized through the provision of a pre-alloy comprising from 5% to nickel, from 20% to 40% copper and from 50% to 75% zinc. Thus, a minimum of 50% zinc may be alloyed with 40% maximum copper and 10% maximum nickel to produce 100% of the pre-alloy. Whereas, a maximum of 75% zinc is alloyable with 20% minimum copper and 5% minimum nickel to produce 100% of the prealloy. It should be understood, however, that while the maxima and minima have been found by repeated tests to be critical for the purposes of this invention, the range within these figures is empirically determined.

terling silver is formed by adding 7.3% of the described pre-alloy to 92.7% of pure silver. The percentage of the alloy and the pure silver may vary within certain limits although it should be noted that sterling silver requires at least 92.7% of pure silver.

The described pre-alloy added to fine silver in varying amounts of alloy to fine silver producing grades alloyed silver, may be used for solders, dental amalgams, electrical contacts, and/or in any place where silver in any degree less than sterling is used.

In accordance with one preferred example, 5% nickel, 25% copper and 70% zinc are mixed together with a suitable flux and when fusion takes place, the molten metal is run into pigs or shots ready for use in the manufacture of sterling silver.

The finished product, capable of use as sterling silver, is 92.7% silver and 7.3% of the pre-alloy.

It was found that the alloy consisting of the above stated range of metals is entirely non-tarnishable and will resist oxidation to a remarkable extent. This applicant wrapped pieces of sterling silver composed of different alloys including his own and others of different percentages, in rubber sheeting and laid them away for months. When the pieces were unwrapped from the rubber, all the samples were black except the alloy prepared in accordance with the present invention. This alloy was still White and untarnished.

Ordinary sterling silver has a bluish sheen rather than a dead white appearance and platinum may be added to the alloy to vary the color of the sterling silver in order to approach the dead white appearance. The pre-alloy of this invention makes unnecessary the use of platinum since it produces a substantially white sterling silver when combined with 92.7% of fine silver. However, where it is desired to accentuate the whiteness of the sterling silver, the pre-alloy may be formed in the following proportions: 10% nickel, 25% copper, 64% zinc and 1% platinum. Sterling silver consists of 7.3% of this prealloy and 92.7% pure silver.

Similarly, the pre-alloy of this invention has been found to give pure silver proper ductility. However, a certain amount of palladium may be added to the pre-alloy to enhance the ductility of the sterling silver. In this event, the alloy may be formed in the following proportions: 5% nickel, 25 copper, 69% zinc and 1% palladium. Sterling silver consists of 92.7 pure silver and 7.3% of the alloy.

It is apparent that the examples set forth above have been given solely by way of illustration and not of limitations and that they are subject to certain variations and modifications without departing from the scope or intent of the present invention so long as they remain within the ranges set forth in the specification. All such variations and modifications are to be included within the scope of the instant invention.

What is claimed is:

1. Sterling silver consisting of 92.7% of fine silver and 7.3 of an alloy consisting of 5% nickel, 25% copper and 70% zinc.

2. Sterling silver consisting of 92.7% of fine silver and .3% of an alloy consisting of 5% nickel, 25 copper, 69% zinc and 1% platinum.

3. Sterling silver consisting of 92.7% of fine silver and 7.3% of an alloy consisting of 5% nickel, 25 copper, 69% zinc and 1% palladium.

References Cited in the file of this patent UNITED STATES PATENTS 338,317 Thowless Mar. 23, 1886 1,321,170 Weiger Nov. 11, 1919 1,612,782 Vogt et al. Dec. 28, 1926 1,651,662 Balke Dec. 6, 1927 1,934,730 Murray et al. Nov. 14, 1933 2,006,598 Muller et al. July 2, 1935 2,058,857 Emmett Oct. 27, 1936 2,187,377 Hensel Jan. 16, 1940 FOREIGN PATENTS 7,195 Great Britain Mar. 26, 1906 110,799 Japan 1936 492,779 Germany Mar. 5, 1930 414,212 Great Britain Aug. 2, 1934 798,964 France Mar. 14, 1936 839,610 France Jan. 4, 1939 OTHER REFERENCES Campbell's List of Alloys, pub. by the Amer. Society for Testing Metals (1930), page 27 relied on. 

1. STERLING SILVER CONSISTING OF 92.7% OF FINE SILVER AND 7.3% OF AN ALLOY CONSISTING OF 5% NICKEL, 25% COPPER AND 70% ZINC. 